package com.xjt.feignsentinel.service;

import com.alibaba.csp.sentinel.adapter.spring.webmvc.callback.BlockExceptionHandler;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.slots.block.authority.AuthorityException;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeException;
import com.alibaba.csp.sentinel.slots.block.flow.FlowException;
import com.alibaba.csp.sentinel.slots.block.flow.param.ParamFlowException;
import com.alibaba.csp.sentinel.slots.system.SystemBlockException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Component;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 自定义限流降级错误信息
 * 也可以请求转发或者重定向其他页面
 */
@Component
public class MyBlockExceptionHandler implements BlockExceptionHandler
{

	@Override
	public void handle(HttpServletRequest request, HttpServletResponse response, BlockException e) throws Exception
	{
		String msg = null;

		// 不同的异常返回不同的提示语
		if (e instanceof FlowException)
		{
			msg = "接口限流了";

		}
		else if (e instanceof DegradeException)
		{
			msg = "服务降级了";
		}
		else if (e instanceof ParamFlowException)
		{
			msg = "热点参数限流了";
		}
		else if (e instanceof SystemBlockException)
		{
			msg = "触发系统保护规则";
		}
		else if (e instanceof AuthorityException)
		{
			msg = "授权规则不通过";
		}

		//返回json数据
		response.setStatus(500);
		response.setCharacterEncoding("utf-8");
		response.setContentType(MediaType.APPLICATION_JSON_VALUE);
		//springmvc 的一个json转换类 （jackson）
		new ObjectMapper().writeValue(response.getWriter(), msg);
	}
}
